const data = '6,3,1;45,2,0;11,1,1;3,19,1;4,7,0;34,7,1;37,5,0;8,8,9;14,72%,28%;46,66%,34%;41,813,323;42,91%,76%;5,8,7;9,1,2;15,29,29;36,18,11;16,0,2;38,12,11;39,9,8;40,17,13;19,12,11;20,2,6;23,4,0;0,,*;43,131,79;44,51,20'

function transformStringToArray (data, key) {
  const arr = data.split(';')
  const list = []
  arr.forEach(item => {
    const itemArr = item.split(',')
    const obj = {
      key: itemArr[0],
      first: itemArr[1] || 0,
      second: itemArr[2] || 0
    }
    list.push(obj)
  })
  return list.filter(item => item.key === key)[0]
}

console.log(transformStringToArray(data, '11'))
